Thermostat



1944- F. D. JOESTING 2,354,814

THERMQSTAT Original Filed Aug. 2, 1940 3 Sheets-Sheet 1 Fig. 2

INVENTOR F/fEDEK/C/f J7. Jowmva BY 1" A ATT RNEY 1944 i F. D. JOESTING2,354,814

THERMOSTAI Original Filed Aug. 2, 1940 3 Sheets-Sheet 3.

INVENTOR I FEEDER/Cl! D. J0$TING ATTORNEY PatentedAug. 1, 1944 UNIT DSTATES PATENT OFFICE THERMOSTA'I.

Frederick 1). Investing, Oak Park, 1b., assignor toMinneapolis-Honeywell Regulator Company, Minneapolis, Minn., acorporation oi Delaware iiriginal application August 2, 1940, Serial No.350,003, nowl'atent No. 2,326,226, dated August 10, 1943. Divided andthis application October 31, 1942, Serial No. 464,014

11 01am. (c zit-21) The present application is a division oi my co- VAnother object is to provide a pneumatic thermostat which can beadjusted to operate either direct acting or reverse acting by virtue ofa novel lever arrangement.

A further object is to provide a novel valve trol air pressure willcause a change in the con-' trol point of the device.

A further object is to provide a pneumatic thermostat oi the day-nighttype in'which provi-- sion is made to place the instrument on its-daysetting when there is an air pressure call for night setting. provisionalso being made for recycling so that the next night shut-down willoccur in the normal manner.

Another object is to provide a thermostat employing a noveltemperaturesetting adjustment combined with a temperature setting indicator and acalibrating adjustment.

Another object is to provide a control point indicator adapted tocooperate with indicia on the instrument cover and also with indiciafixed to the instrument base on which the control point may be read whenthe cover is removed."

A further object is to provide a thermottat having an expansiblepressure chamber operable lowing description, from the claims and fromthe drawings, in which:

Figure 1 is a front view of a thermostatjas it would appear mounted on awall,

Figure 2 is a sectional view taken substantially on line 2-2 of Figure1, I v

Figure 3 is a sectional view of the thermostat of Figure 2 and takensubstantially on line 3-3 of Figure 2,

Figure 4 shows th valve mechanism with the upper part removed,

Figure 5 is a sectional view of the valve mechanism taken substantiallyon line 55 of Figon the thermostat mechanism to change the con- .trolpoint. Further ure 4,

Figure 6 is a sectional view of the day-night relay mechanism of thethermostat shown in Figure 2, 1 Y

Figure 7 shows a modified form of this thermostat, and

. Figure 8 shows the temperatur setting mechanism oi the thermostat.

The thermostat shown in Figures 1 through 6,

and 8 is a pneumatic thermostat adapted to control the temperature in aspace at one point during the day and at a lower temperature during thenight. The changeover from day to night setting is accomplished bychanging the pressure of the air which is supplied to the thermostat forcontrol purposes;

Figure 1 shows a front view of the thermostat withthe cover in place.The cover l0 is provided with an opening H through which may be seen atemperature setting indicator 12 which will be more fully describedhereinafter. Ad- Jacent the opening I! on the cover l0 are indicia itwhich cooperate with the indicator E2 to show the temperature setting ofthe device. A second opening H6 in the cover In is provided to afford aview of a glass thermometer it which is mounted on the underside of thecover. Suitable indicia H are provided on the cover it to cooperate withthe thermometer, it- As seen in Figure 2 the thermometer it isfrictionally secured beneath the cover by means of clamp it in a mannerto provide an adjustment of the thermometer tube with respect to thecover for purposes of calibration. The tube may be later fixed withrespect to'the cover by a fast drying cement such as ambroid. The coveri0 is seated on a wall plate It which is suitably secured to a mainframe 2| which serves to secure the various parts of the thermostat inoperative position.

The frame 2| is provided withtwo parallel por-.

tions 23 and 24 which extend into the cover Ill. The portion 23 of theframe-2i has secured thereto a volatile filled expansible bellows 25which on expansion and contraction serves to rotate a main lever 28about its pivots 30 in the frame 2 I. See Figure 3. The lever 28 issubstantially T-shaped having a portion extending vertically as seen inFigure 2 to cooperate with the bellows 25 and a horizontally extendingportion 3| to the right of the pivot 30 and a second horizontallyextending portion 33 to the left of the pivot 30. Resistingcounter-clockwise movement of the lever 28 by the bellows 25 is a mainspring 35 which bears against an abutment 36 provided on the upstandingportion of the lever 28. bears against a nut 31 which is adjustable onthe exterior of a second nut 38. turn is positioned on a, temperatureadjusting screw 40 which is provided with a head 42 having a flange 4|which abuts the portion 24 of the frame 2|. The head 42 of screw 48 isprovided with a squared portion 43 by means of which the screw 40 may berotated with respect to the frame 2|. Referring to Figure 8 it will beseen that the nut 38 has secured thereto the temperature settingindicator ll heretofore referred to.

Secured to the portion 24 of the frame 2| is an indicia plate 46 havingindicia thereon corresponding to the indicia l3 on the cover I8. As willbe seen from Figure 2 the indicator ll lies between the indicia plate 46which is mounted on the frame and the cover It. With this structure itwill be seen that the indicator H cooperates with both sets of indiciaso that when the cover is in place the temperature setting may be readon the indicia I3 and when the cover is removed the temperature settingis visible on the indicia plate 46. provided with an extension 48 whichextends through a slot 49 in .the indicator II to prevent rotation of.the nut 38 with respect to the frame 2|. The shaded lines on the upperportion of the indicator ll show that the indicator is colored somesuitable color such as red to provide a readily visible indication ofthe temperature setting. The nut 31 is adjustable on the nut 38 in orderto provide a calibration adjustment so that the tension of the spring 35will be sufficient to balance the bellows when the space temperature isat the setting shown by the indicator H. Y

The main lever 28 is provided with a slot 50 in its lower portion whichextends substantially the entire lengthof both portions 3 l and 33 asshown in Figure 3. Adjustably secured in this slot is an abutment 52which is provided with suitable means for fastening it in any desiredposition along the slot. This abutment 52 is adapted to cooperate with asecondary lever 54 which is pivoted at its left hand extremity in abracket 55 secured-to the portion 24 of the frame 2| as seen in Figure2. It will be seen that main lever 28 and secondary lever 54 aredisposed in parallel relationship so that the abutment 52 may be movedfrom one point to another on lever 28 without changing the angularrelationship between the main and secondary levers.

Mounted on the back part of the frame 2| is a The left hand end of thespring 35,

The nut 38 in The indicia plate 46 isnism is shown in Figures 4 and 5.Briefly the function of the valve mechanism 56 is to supply a pressureto a branch air line which is dependent on the temperature of thetemperature re-- sponsive bellows 25. Air is supplied under pressure toone port of the valve, this pressure being admitted in a chambercommunicating with the branch line at such times as the thermostat callsfor increased pressure. When a smaller pressure is required an exhaustport is opened to reduce the pressure in the chamber. As will be pointedout hereinafter, both valves are never open at the same time. One isalways closed be fore the other is opened. In this way any suitablecontrol mechanism such as a valve or damper may be suitably positioned.The true relation of the valve ports is shown in Figure 4 which is aview of the valve mechanism 58 with the upper portion 59 removed. InFigure 5 the lateral relation of the parts has been distorted somewhatin order to more clearly show the operation of this. device. Theadjustable connection 58 which connects with the secondary lever valvemechanism 55 which is operated by the secondary lever 54 through anadjustable connection 54 is secured to a diaphragm 60 which is clampedin place in the upper portion 59 of the valve by means of a ring 6|. Aball 63 serves to transmit the force supplied to the adjustableconnection '58 to a valve operatingmember B5. The ball 63 acts merely asa pressure transmitting member and never interferes with thetransmission of air pressure to the diaphragm 60. The member 65 ispositioned to engage and actuate the ball valves 61 and 10 which controlthe exhaust port 68 and supply port 12, respectively. These valves arebiased upwardly to open position, as seen in Figure 5, by springs 13 and14 which therefore also bias member 65 upwardly. Spring 16 furtherbiases member 65 upwardly. and the under sides of the heads of screws 18and 88 act to limit the upward movement of member 65.- When no downwardforce is being exerted by ball 63 on member 65 the springs 16 and 13maintain the supply valve 18 seated due to the reaction of the member 65along the line A-B formed by the two stops [8 and while the exhaustvalve 61 is open due to the action of the spring I3.

The ball 63 is so arranged with respect to the member 65 that as theball 63 presses downwardly on the member 65 such force is applied to themember so as to rotate the member 65 about the axis AC formed by theseated ball valve I0 and the under side of the head of screw 18. Thespring 15 is so located as to produce a moment on member 65 about screw18 and ball 63 which will hold the ball valve 18 in closed positionagainst the action of spring 14 until the ball valve 61 is seated. Thisaction closes valve 61 and also compresses biasing spring '16 somewhat.It will be noted that in this position of the member 55 both valves areclosed and ths position may therefore be referred to as the normal"position. Further downward pressure by the ball 83 will cause member 65to rotate about the axis AD formed by the seated ball valve 61 and theunder side of the head of screw 18. This rotative movement will permitbiasing sprin I4 to open the ball valve 10 controlling the supply port.Thus it will be seen that the valve 10 can only be opened after closureof the valve 81. A reduction in pressure by the ball will obv ouslycause opposite movement of the member 65 to first close the supply valve10 and then open the exhaust valve 61. The inlet and exhaust ports 12and 58, the screws 18 and 80, and the spring are all disposed in thelower part 82 of the leads to the pressure responsive device to becontrolled.

With the abutment 52 between the main lever 28 and the secondary lever54 in the position shown to the left of the pivot 30 for the lever 28the action of the thermostat will be direct act ing" which means'that asthe pressure in the bellows increases as a result of a temperatureincrease; the pressure supplied to the branch line willincrease. Thismay be explained as follows:

When the temperature responsive bellows 25 is satisfied the primarylever 28 and secondary lever 54 will hold the valve actuating member 55in normal position at which time both the supply andexhaust valves 10and 61 will be closed. Onan increase in temperature the bellows 25 willexpand and rotate the primary lever 28'in a counter-clockwise direction.The secondary lever 54 will be moved clockwise by the primary leverthrough the abutment 52 to force the adjustable connection 58 to thevalve mechanism 55 downwardly. This will result in the ball 63 openingthe inlet port by permitting the ball 10 to rise from its seat slightly.The pressure within the chamber formed by the upper and lower portions59 and 82 of the valve 55 will rise and this increase in pressure willbe supplied to the underside of the diaphragm 6D tending to rotate thesecondary lever 54 in a counter-clockwise direction and the main lever28 in a clockwise direcmember 65 through the ball 63 and the adjustableconnection 58 and the pressure under the diaphragm 68 will permit themember 65 to pivot about the under side of the head of the screw 18 andthe ball 10 thus opening the exhaust port. The ball 61 controlling theexhaust port will bleed pressure from the space beneath the diaphragm 68reducing the force acting upwardly on the adjustable connection 58. Asthis force is reduced the secondary lever 54 will rotate slightly in'aclockwise direction and the force on the abutmain lever 28. If theabutment 52 is now moved to the portion ll of the lever 28 to the rightof the pivot 30the thermostat will be of the "reverse acting type. -Inthis position of the abutment 52 it will be seen that the pressurebeneath the diaphragm 50 in the valve mechanism 55 will be exertedthrough the secondary lever 54. and the main lever 28 to assist ratherthan oppose theforce of the bellows 25. Thus on an increase intemperature the bellows 25 will rotate the main lever 28 in acounter-clockwise direction and the secondary lever 54 will also berotated in a counter-clockwise direction. Assuming the valve 55 to be innormal position with both inlet and exhaust ports closed, this decreasein force on the adjustable connection 58 will serve to open the exhaustport to relieve the pressure beneath the diaphragm 50. This will againcause the secondary lever 54 to rotate in a clockwise direction.The'upward force on the right hand end of the main lever 28 will berelieved slightly and the spring will collapse the bellows 25 to itsnormal position. -If the temperature of bellows 25 is reduced the mainlever 28 will be rotated slightly in a clockwise direction and thesecondary lever 54 will be forced downwardly to open the inlet port ofthe valve 55. This will result in an increase in pressure beneath thediaphragm 80 to increase the upward force on the secondary lever 54.Likewise there will be present a force tending to rotate the main lever28 counterclockwise to assist the bellows 25 in returning the valve toits normal position.

This will reduce the force transmitted to the I ment 52 will be relievedpermitting the bellows 25 secondary lever 54, and in the operation ofthe thermostat described above the abutment 52.was

assumed to be to the leftof the pivot 38 for the Thedifierentialadjustment. of the device will be described assuming the abutment 52between the main and secondary levers to be to the left of the pivot 30to cause the device to be direct acting. It will be understood that asimilar adjustment may be had when the thermostat is set up to bereverse acting. By differential is meant the change, in temperature atthe bellows 25 necessary to vary the pressure beneath the diaphragm 50,and therefore the branch line pressure, between the maximum and minimumvalues which'will operate whatever control de- .vice is connected to thebranch line from one extreme position to the other. The control devicemay be a steam valve operable from wide open to closed positions. It iscommon practice to supply compressed air at 15 pounds per square entialof the thermostat will be relatively small while if the abutment 52 ismoved further to the left the difierential will be increased. At

zero branch line pressure the temperature responslve bellows 25 issubstantially balanced by the spring 35 and no force is transmitted tothe diaphragm other than that necessary, to bal-v ance the effect f thespring Hi. In order to maintain any particular branch line pressuregreater than zero a certain force must; be exerted downwardly on thediaphragm 80 to balance the pressure beneath diaphragm '88. Thecounter-clockwise force acting on lever 28 necessary to produce thisforce at the diaphragm 55 will depend, therefore, on the position of theabutment 52. As the abutment 52 is moved :l'arther to the left theleverage of bellows 25 on the diaphragm 68 will be reduced andconsequently ay ep a greater increase in bellows temperature andnecessary to balance the branch line pressure. In other words, with theabutment 52 positioned far from the pivot for the lever 28 a greatertemperature change isnecessary to cause the same to change in force onthe diaphragm 69 than when the abutment 52 is positioned near the pivot39.

The thermostat as shown in Figures 1, 2, and 3 is of the day-night type.The temperature selected and indicated on the indicia represent thedaytime setting. The night temperature setting will be at a valuesomewhatbelow this value. A supplementary bellows 99 is mounted in thebottom portion of the frame 2I as seen in Figure 2 and is normallysupplied with air under pressure to compress a, spring 92 which actsthrough an abutment 93 to pull downwardly on a lever 95 -through aconnection 96 as seen in Figures 2 and3. The lever 95 is pivoted on abracketsupportedby the portion 24 of the frame 2I and normally lies inthe same plane as the secondary lever 54. An adjustable connection 91mounted in the main lever 28 is adapted to'transmit clockwise movementsof the lever 95 to the main lever 28. It will be seen therefore thatwith the supplementary bellows 99 in its expanded position the spring 92will be compressed and no force can be transmitted from the spring 92 tothe lever 95 or to the main lever 29. When the pressure within thebellows 99 is relieved the spring 92 forces the abutment 93 downwardlyand the. force is transmitted the main calibrating spring 35. The netresult is the same as reduction in the tension of the spring byadjustment of the temperature setting mechanism and the thermostat willcontrol at a lower temperature.

As was indicated diaphragm II 9 toward the right is retained at its lefthand end by a plate I I4 which is adjustably screw threaded into thebase I95. By adjusting the plate H4 in the base I95 the tension of thespring I I2 may be varied and therefore the pressure within the chamberI98 necessary to force the diaphragm H0 toward the left may be adjusted.The connection I 94 which leads to the bellows 99 is provided with twoports H6 and H1 within the base.l95. The port H6 is closed by a springstrip H9 which is mounted on the base I95. The port II! is likewiseclosed by aspring strip I2I mounted on the'base I95 but within thechamber I98. Both spring strips H9 and I2I are biased to close theirrespective ports. Secured to the diaphragm H9 is an abutment I29 whichis adapted to force the spring strip I2I to the right to open' the portII'I when the pressure within the chamber I98 is at a relatively lowvalue. Screw I25 is adjustably secured to the diaphragm H9 and serves tomove the blade H9 to the left to open the port H6 when the pressurewithin the chamber I98 is at a relatively high value. Normally the screwI25 is so adjusted that the blade H9 will not open the port H6 until theblade I2I has closed the port III. Normally the relay mechanism is soadjusted that when the pressure in the supply line is at 13 lbs. persquare'inch the diaphragm H0 is moved to the right by the spring H2 toopen the port H1 and close'port H9 and supply the full 13 poundspressure to the bellows 99. This is the normal-daytime pressure in thesupply line; At night the supply line pressure'is raised to 17 lbs. persquare inch and the. diaphragm H9 is forced to the left to close theport H1 and open the port H6. This exhausts the pressure within thebellows 99 and places the thermostat on its night setting by allowingthe above, the connection 91 between the'main lever 29 and the lever 95is adjustable. A slot l99 as seen in Figure 3 is provided in the mainlever 29 for movement of the connection 91 lengthwise of the lever 29. Acorresponding slot is pro- Also mounted in'theunder part of the frame2I- is a day-night'relay' mechanism I92, see Figure 2, which is slfownin cross section in Figure 6. This relay mechanism I92 is connected by apipe- .I99 to the inlet port of the main valve 59 t provide pressurewithin the resupply pressure. A pipe mechanism. I92 to V e" funct ionofthe day-nightv relay-.lnechanism is=tochange thetpressure with inthebellows 99 from atmospheric pressure to,

supplyline pressurebn a .small 'changein-supply linepressure-..Referring to Figured the relay mechanism I92 a base I99 anda. cover I91 screw threaded thereto. Supply line air pressure issupplied-to a" chamber I99intermediate the base I-for the cover I91.Mounted within the base I99 is a diaphragm III which is subject tosupply line pressure on its right hsndside and to atmospheric pressureon its spring 92 to exert its force in a. counter clockwise direction onthe main lever 29 of the thermostat. In practice the relay mechanism isadjusted to supply line pressure to the bellows 99 or exhaust thebellows 99 on a change in supply line pressure of 1 pound oer squareinch.

As seen in Figures 1, 2, and 3 a shaft I99 is pivoted in a bracket I!which is secured to the extension 24 of the frame 2I. The purpose ofthis shaft is to enable the thermostat to be placed on the daytimesetting when the branch line pressure has been adjusted to the nightvalue. The shaft I99 extends outside the cover I9 and is provided withhandle I94 on its outer end. By rotating the handle I94 in a clockwisedirection from the position shown in Figure 2 a screw I99 extendingthrough the shaft I99 will force an upstanding portion I'99.of the lever99 to the left. This will cause the lever 95 to rotate macouhter-clockwise direction to tension the spring 92 and rellevethedownward force or the lever 99 on the connection 91 and thereforerelieve the main lever 29 of the force exerted by the spring 92. It willbe seen that this Opera- 'tionrof the handle I9|7is effective to'returnthe whichis'securedtotheportion 24 oftlieframe 2| at one of its ends andto the shaft I99 at its left hand side; A spring II2 which biases the19' other end biases the shaft I99 in a eounterrclockwise direction andserves to returnthe shaft I99 plied with air under pressure. I! thethermostat is calling for night setting, and the handle I is rotated inaclockwise direction, it will remain- I30 is in the position whichrenders the spring 92 inoperative to depress the temperature set.- ting.The thermostat is thereby locked in the day setting. This feature isdesired in some applications where one or more rooms are occupied duringthe evening, while the rest of the building is maintained at a lowertemperature. The thermostats in these rooms can thus be set to maintainday temperatures all the time.

The modification of the thermostat shown in Figure '7 is of the typeknown in the art as a second closing means inopposition to the force Ito rotate said member about said second closing chamber, first andsecond closing means for said first and second ports respectively,means-biasing said closing means toward open position, a member adaptedto engage said closing means to close the same, a pivot for said memberlocated at a point out of line with the points of contact between saidmember and said closing means whereby said member may be rotated onaxes' including said pivot and either closing .means,

biasing means acting on said member to close said first closing means,actuating means acting on said member and adapted to rotate said memberabout said first closing means to close said of said. biasing means andoniurther movement means to open said first closing means, whereby atleast one of said port closing means is,

maintained in, closed position for all positions of said actuatingmeans.

3. In a fiuid pressure control device, in combination, a chamber, firstand second ports in sub-master thermostat. In such a thermostat thecontrol point is varied by the variations in pressure caused by a masterthermostat. The construction of this thermostat is similar in mostrespects to the day-night thermostat described above except that theauxiliary bellows is adapttion and to force the main lever 28a inaclockwise direction through the connection 97a to assist the calibratingspring rather than to oppose it. Likewise the pressure in the auxiliarybellows is changed gradually over its entire range by a masterthermostat rather than by changes in supply line pressure. Thus it willbe seen that no increases in pressure in the auxiliary bellows the mainlever 2811 will be forced in clockwise'direction to increase thecontrolpoint of the instrument. Similarly reductions in pressure in theauxiliary bellows will relieve the force on the main lever 28a opposingthe temperature responsive bellows and result in the thermostatcontrolling at a lower temperature.

While the foregoing description represents the preferred form 01 theinvention at the present time, it will be understood that variousmodifications could be devised by those skilled in the .art, whichmodifications would come within the spirit of the invention. 1- am,therefore to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a fluid pressure control device, in combination, a chamber, firstand second ports in said chamber, first and second closing means forsaid first and second ports respectively, means biasing said closingmeans toward open position, a member adapted to engage said closingmeans ed to force the lever 95a in an upwardly direcsaidchamber,firstand second closing means for said first and second portsrespectively, means,

biasing said closing means toward open position,

a member adapted to engage said closing means to close the same, a pivotfor said 'member located at a point out of line with the points ofcontact between said member and said closing means whereby said membermay be rotated on axes including said pivot and either closing means,biasing means acting on said member to close said first closing means,actuating means acting on said member and adapted to rotate said memberabout said first closing means tov close said second closing means inopposition to the force of said biasing means and on further movement torotate said member about said second closing means to open said firstclosing means, whereby-at 'least one of said port closing means ismaintained in closed position for all positions of said actuating-means,and a stop to engage said member when said actuating means applies noforce thereto-for acting-as a supplementary pivot about which saidmember is biased to'close-said first closing means.

4. A fluid'pressure control device comprising the combination of achamber having an opening therein, a diaphragm closing the opening,inlet and exhaust ports in said chamber, port closing means for saidports, means biasing said port closing means to open position, amemberadapted to engage said closing means to close the same, anactuating element operatively connected to said member and to saiddiaphragm, a pivot for said member located out of line with said portclosing means, a spring biasing said member to closethe port closingmeans for said inlet port and to open the port closing means 'for saidexhaust port, the arrangement being such that assaid actuating elementactuates said to close the same, biasing means acting on said member toclose said first closing means, actuating means acting onsaid member andadapted to rotate said member about said first closingmeans to closesaid second closing means in oppositionto the force of said'biasingmeansand on further movement to rotate said member about said second closingmeans to open said first closing means, whereby at least'one of saidport closing means is maintained in closed position for all positions ofsaid actuating means.

2. In a. fluid pressure control device, in combination, a chamber, firstand second ports in said member it will rotate about said pivot and saidport closing means for said inlet port to close the port closing meansfor said exhaust port and on further movement by said actuating elementsaid member will rotate about said pivot and said port closing means forsaid exhaust port to open said port closing means for said inlet port.

5. ha fluid pressure-control device, in combination, a chamber, inletandexhaust ports in said chamber, closing means for said ports, meansbiasing said closing meanstoward open position, a member adapted toengage said closing means normally to close both of said ports, biasingmeans tending to rotate said member about its pointof ing means tendingto move it, and a diaphragm closing an opening in said chamber andmovable with said actuating means, whereby the pressure in said chamberwill be maintained at a value to position said member through saiddiaphragm and said actuating means at its normal position in which boththe inlet and exhaust ports are closed.

6'. In a fluid pressure control device, in combination, a chamber, inletand exhaust ports in said chamber, closing means for said ports, meansbiasing said closing means toward open position, a member adapted toengage said closing means normally to close both of said ports, a pivotfor said member located at a point out of line with the points ofcontact between said member and said closing means whereby said membermay be rotated on axes including said pivot and either closing meanstoopen said ports selectively.

biasing means tending to rotate said member' about its point of contactwith said inlet port closing means to open said exhaust port, actuatingmeans extending out of said chamber and adapted to rotate said memberabout its point of contact with said exhaust port closing means to opensaid inlet port, means for exerting a force on said actuating meanstending to move it in opposition to. said biasing means, "and adiaphragm closing an opening in said chamber eration 01' said first andsecond control means by said first and second biasing means, a thirdbiasing means for actuating said member to a first position opposing theoperation of said first control means by said first biasing means andpermitting the operation of said second .control means by said secondbiasing means, actuating means for actuating said member to a secondposition opposing the operation of both said control means by said firstand second biasing means, and said actuating means arranged in such amanner as to actuate said member to a third position opposing theoperation of said second con-- trol means by said second biasing meansand permitting the operation of said first control means by said firstbiasing means.

9. A control device, comprising, in combination, first and secondcontrol means, first bias- 7. In a fluid pressure control device, incombination, a chamber, inlet and exhaust ports in said chamber, closingmeans for said ports, means biasing said closing means toward openposition, a member adapted to engage said closing means normally toclose both 'of said ports, biasing means tending to rotate said memberabout its means to open said exhaust port, actuatingmeans extending outof said chamber and adaptedf to rotate said member about its point ofcontact with said exhaust port closing means to open said inlet port, adiaphragm closing an opening in, said chamber and movable with saidactuating means, a first pivoted lever. engaging said actuating means, asecond lever normally parallel to said first lever and pivoted at apoint inter- -mediate the pivot forsaid first lever and the point ofcontact between said first lever and said point of contact with saidinlet port closing actuating means, force transmitting meansinengagement with both of said levers, said trans mitting means being'movable lengthwise of said levers, a device operatively connected tosaid second lever tending to rotate said lever inone. direction orpermit its'rotation in the opposite "direction, a spring opposingrotation of said sec control means, a. member for controlling the opingmeans for operating said first control means and second biasing meansfor operating said second control means, a member for controlling theoperation of said first and second control means by said first andsecond biasing means, a third biasing means for actuating said member toa first position opposing the operation of said first control means bysaid first biasing means and permitting the operation of said secondcontrol means by said second biasing means, actuating means foractuating said member to a second position opposing the operation ofboth said control means by said first and second biasing means, saidactuating means arranged in such a manner as to actuate said member to athird position opposing the operation of said second control means bysaid second biasing means and permitting the operation of said'firstcontrol means by said first biasing means, and means for operating saidactuating means controlled by said first and second control means.

'10. A control device, comprising, in combination, first and secondcontrol means, first biasing means for operating said first controlmeans and second biasing means for operating saidsecond control means, amember for controlling the op-" eration of said first and second controlmeans by said first and second biasing means, a third biasing means foractuating said member to a first position opposing the operation of saidfirst control means by said first biasing means and permitting theoperation of said second control means by said second biasing means,actuating means for actuating said member to a second position opposingthe operation of both said control means by said first and secondbiasing means, said actuating means arranged in such a mannet as toactuate said member to a third position opposing the operation of saidsecond control means by said second biasing means and permitting theoperation of said first'control means by said first biasing means, meansfor moving said actuating means so as to move said member I fromsaidsecond position to said first or third positions depending on theforce exerted by said v last means, and means controlled by said firstand second control means 101- returning said member to said secondposition.

" 11. In a fiuid pressure control device, comprisins. in combination, achamber, an inlet port'and an exhaust port in said chamber, a'first ballvalve for controlling one of said ports and a second ball valve forcontrolling the other of said ports, first spring means for biasing saidfirst ball valve to an open position, second spring means for biasingsaid second ball valve to an open position, a member resting at one endupon said ball valves.

asses 7 a' first element for pivotally mounting said member positionedadjacent the first of said ball valves, and to one side of the second ofsaid ball valves, a third spring means for exerting a biasing force uponsaid member at a point at the op-' posite side of said first elementfrom said ball valves and at a side of said first element at which saidsecond ball valve is mounted whereby thebiasing force of said secondspring means and said third spring means opposes the biasing force 10 ofsaid first spring means and thereby pivots said member so as to actuatethe firstball valve in such a manner as to close the port controlledthereby, a second element for limiting the movement of said member inresponse to said biasing forces, an actuating ball exerting a force uponsaid member at a point at the same side oi-said pivot as said secondball valve and intermediate said second ball valve and said third springmeans in such a manner as to pivot said member

